Paper feeding device and paper feeding method applied thereto

ABSTRACT

A paper feeding device includes a motor, a pickup roller assembly, a velocity sensor and a feeding roller assembly. The pickup roller assembly is driven by the motor for picking up the papers. The velocity sensor is mounted to the pickup roller assembly for detecting rotating speeds of the pickup roller assembly so as to detect speeds of feeding forward the papers. The feeding roller assembly is driven by the motor for continuing feeding forward the papers. A speed discrepancy will be generated between the rotating speed of the pickup roller assembly after the one of the papers is fed to the feeding roller assembly and the rotating speed of the pickup roller assembly which just picks up the one of the papers, when the speed discrepancy reaches a preset value set by the scanner, the scanner is triggered to start scanning.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to a paper feeding device, and more particularly to a paper feeding device mounted in a scanner capable of having a better scanning effect and a lower cost, and a paper feeding method applied thereto.

2. The Related Art

Generally, a current paper feeding device is mounted in a scanner, includes a pickup roller assembly, a feeding roller assembly, a scan sensor and a motor. The motor drives the pickup roller assembly to rotate for picking up papers and transmitting the papers to the feeding roller assembly. The feeding roller assembly feeds forward the papers transmitted by the pickup roller assembly. When a front edge of each of the papers touches the scan sensor, a scanning switch is triggered and a scanning process is started. The current paper feeding device is also able to be mounted in a multifunctional printer.

However, a cost of the scan sensor is higher, and the scan sensor can just trigger the scanning switch, speeds of feeding the papers are incapable of being known, the speeds of feeding the papers are nonuniform that will make scanned images shortened or stretched. As a result, the scanner including the current paper feeding device has a worse scanning effect and a higher cost thereof.

Thus, an innovative paper feeding device and a paper feeding method applied thereto are essential to be provided, the scanner including the innovative paper feeding device is capable of having a better scanning effect and a lower cost.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a paper feeding device mounted in a scanner for feeding papers. The paper feeding device includes a motor, a pickup roller assembly, a velocity sensor and a feeding roller assembly. The pickup roller assembly is connected with and driven by the motor for picking up the papers and transmitting the papers to the feeding roller assembly. The velocity sensor is mounted to the pickup roller assembly for detecting rotating speeds of the pickup roller assembly so as to detect speeds of feeding forward the papers. The rotating speed of the pickup roller assembly is detected by virtue of counting pulses outputted by the velocity sensor. The feeding roller assembly is connected with and driven by the motor, and is located in front of the pickup roller assembly for continuing feeding forward the papers. A rotating speed of the feeding roller assembly is faster than the rotating speed of the pickup roller assembly. After one of the papers is fed to the feeding roller assembly, the feeding roller assembly drives the one of the papers to be fed accelerately, at the moment, the pickup roller assembly rotates accelerately on account of being dragged by the one of the papers, a speed discrepancy will be generated between the rotating speed of the pickup roller assembly after the one of the papers is fed to the feeding roller assembly and the rotating speed of the pickup roller assembly which just picks up the one of the papers, when the speed discrepancy reaches a preset value set by the scanner, the scanner is triggered to start scanning.

Another object of the present invention is to provide a paper feeding method applied to a paper feeding device which is mounted in a scanner for feeding papers. The paper feeding device includes a motor, a pickup roller assembly connected with the motor, a velocity sensor mounted to the pickup roller assembly, and a feeding roller assembly connected with the motor. Steps of the paper feeding method are described hereinafter. The motor drives the pickup roller assembly to rotate to pick up the papers and transmit the papers to the feeding roller assembly. The velocity sensor detects rotating speeds of the pickup roller assembly by virtue of counting pulses outputted by the velocity sensor so as to detect speeds of feeding forward the papers. The motor drives the feeding roller assembly to rotate for continuing feeding forward the papers transmitted by the pickup roller assembly to a scan passageway of the scanner. Get a speed discrepancy between the rotating speed of the pickup roller assembly after the one of the papers is fed to the feeding roller assembly and the rotating speed of the pickup roller assembly which just picks up the one of the papers, when the speed discrepancy reaches a preset value set by the scanner, the scanner is triggered to start scanning.

As described above, the speeds of feeding forward the papers are able to be detected in real time by virtue of the velocity sensor being fastened to the pickup roller assembly of the paper feeding device, and a scan scaling of the scanner is correspondingly modulated according to the speeds of feeding forward the papers, so that scan images will be without being shortened or stretched in the scan process for improving quality of the scan images. In addition, the speed discrepancy will be generated between the rotating speed of the pickup roller assembly after the one of the papers is fed to the feeding roller assembly and the rotating speed of the pickup roller assembly which just picks up the one of the papers, and the scanner is triggered to start scanning when the speed discrepancy reaches the preset value, so the papers are able to be scanned in real time in no need of the scan sensor. As a result, the scanner applying the paper feeding device is capable of having a better scanning effect and a lower cost.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be apparent to those skilled in the art by reading the following description, with reference to the attached drawings, in which:

FIG. 1 is a perspective view of a paper feeding device in accordance with an embodiment of the present invention;

FIG. 2 is a schematic diagram of the paper feeding device of FIG. 1 being mounted in a scanner;

FIG. 3 is a schematic diagram of a pulse frequency variation of a velocity sensor of the paper feeding device of FIG. 1 under a condition of the pickup roller assembly being in different rotating speeds; and

FIG. 4 is a flow chart of a paper feeding method being applied to the paper feeding device of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIG. 1 and FIG. 2, a paper feeding device 100 in accordance with an embodiment of the present invention is shown. The paper feeding device 100 is mounted in a scanner (not shown) for feeding papers 200. The paper feeding device 100 includes a motor 40, a pickup roller assembly 10, a velocity sensor 20 and a feeding roller assembly 30.

Referring to FIG. 1 and FIG. 2 again, the pickup roller assembly 10 is connected with and driven by the motor 40. The pickup roller assembly 10 includes a pickup shaft 11, and a pickup roller 12 pivotally mounted around one end of the pickup shaft 11. The pickup roller assembly 10 is used for picking up the papers 200, and transmitting the papers 200 to the feeding roller assembly 30.

Referring to FIG. 1 to FIG. 3, the velocity sensor 20 is mounted to the pickup roller assembly 10. Specifically, the velocity sensor 20 is mounted to the pickup shaft 11 of the pickup roller assembly 10 for detecting rotating speeds of the pickup roller assembly 10 so as to detect speeds of feeding forward the papers 200. The velocity sensor 20 is an optical rotary encoder. The velocity sensor 20, namely the optical rotary encoder includes a light source 21, a coded disc 22 and a light receiver 23. The coded disc 22 opens a plurality of equidistant openings 221 arranged as a ring shape. The coded disc 22 is fastened to the other end of the pickup shaft 11. The coded disc 22 is disposed between the light source 21 and the light receiver 23. When the scanner is started, the light source 21 is turned on.

The motor 40 drives the pickup roller assembly 10 to rotate to pick up the papers 200 and transmit the papers 200 to the feeding roller assembly 30. When the motor 40 drives the pickup roller assembly 10 to rotate to pick up the papers 200, the pickup shaft 11 and the coded disc 22 rotate together at the same speed. The light source 21 and the light receiver 23 are without rotating with the pickup shaft 11. The light receiver 23 receives light beams penetrating through the openings 221 at the time of the pickup shaft 11 and the coded disc 22 rotating together. The velocity sensor 20 outputs pulses corresponding to the openings 221. So a rotation amount of the pickup roller assembly 10, namely the rotating speed of the pickup roller assembly 10 is detected by virtue of counting the pulses outputted by the velocity sensor 20.

Referring to FIG. 3, a schematic diagram of a pulse frequency variation of the velocity sensor 20 under a condition of the pickup roller assembly 10 being in different rotating speeds is shown in FIG. 3. Within preset time, the higher a pulse frequency of the velocity sensor 20 is, the more a quantity of the pulses per unit time is, namely the faster the rotating speed of the pickup roller assembly 10 is; the lower the pulse frequency of the velocity sensor 20 is, the less the quantity of the pulses per unit time is, namely the slower the rotating speed of the pickup roller assembly 10 is.

Referring to FIG. 1 and FIG. 2 again, the feeding roller assembly 30 is connected with and driven by the motor 40, and is located in front of the pickup roller assembly 10 for continuing feeding forward the papers 200 transmitted by the pickup roller assembly 10 to a scan passageway 300.

Referring to FIG. 1 to FIG. 3, when the paper feeding device 100 is working, the motor 40 drives the pickup roller assembly 10 and the feeding roller assembly 30 to rotate, and the pickup roller assembly 10 and the feeding roller assembly 30 rotate in different rotating speeds. The rotating speed of the feeding roller assembly 30 is faster than the rotating speed of the pickup roller assembly 10. The pickup roller assembly 10 rolls to pick up the papers 200 and the papers 200 are fed forward in a preset speed. After one of the papers 200 is fed to the feeding roller assembly 30, the feeding roller assembly 30 drives the one of the papers 200 to be fed accelerately, at the moment, the pickup roller assembly 10 rotates accelerately on account of being dragged by the one of the papers 200. A speed discrepancy will be generated between the rotating speed of the pickup roller assembly 10 after one of the papers 200 is fed to the feeding roller assembly 30 and the rotating speed of the pickup roller assembly 10 which just picks up the one of the papers 200.

S1 shown in FIG. 3 is the pulse frequency of the velocity sensor 20 when the pickup roller assembly 10 just picks up the papers 200. S2 shown in FIG. 3 is the pulse frequency of the velocity sensor 20 when the feeding roller assembly 30 drives the papers 200 to be fed accelerately. S3 shown in FIG. 3 is the pulse frequency of the velocity sensor 20 when the papers 200 is apart away from the pickup roller assembly 10. The speed discrepancy is got by virtue of the variation of the pulse frequency of the velocity sensor 20 every time. When the speed discrepancy reaches a preset value set by the scanner, a scan switch (not shown) of the scanner is triggered to start scanning.

A time point of the scanner applying the paper feeding device 100 scanning each of the papers 200 is the same as a timeliness of a conventional scan being proceeded by virtue of each of the papers 200 touching a scan sensor (not shown), so that the papers 200 are able to be scanned in real time in no need of the scan sensor. In the scan process, the speeds of feeding forward the papers 200 are able to be detected in real time according to the pulse frequency variations of the velocity sensor 20, and a scan scaling of the scanner is correspondingly modulated according to the speeds of feeding forward the papers 200, so that scan images of the papers 200 will be without being shortened or stretched in the scan process for improving quality of the scan images. Paper jam problems are also able to be detected in the process of feeding the papers 200 by virtue of getting the pulse frequency variations of the velocity sensor 20, so that instructions are sent at the time of the paper jam problems being detected, and the motor 40 is stopped rotating for preventing the papers 200 from being damaged.

The paper feeding device 100 is also able to be mounted in a multifunctional printer (not shown).

A paper feeding method in accordance with an embodiment of the present invention is shown. The paper feeding method is applied to the paper feeding device 100 which is mounted in the scanner for feeding the papers 200. Specific steps of the paper feeding method are described as follows.

The motor 40 drives the pickup roller assembly 10 to rotate to pick up the papers 200 and transmit the papers 200 to the feeding roller assembly 30.

The velocity sensor 20 detects the rotating speeds of the pickup roller assembly 10 by virtue of counting the pulses outputted by the velocity sensor 20 so as to detect the speeds of feeding forward the papers 200.

The motor 40 drives the feeding roller assembly 30 to rotate for continuing feeding forward the papers 200 transmitted by the pickup roller assembly 10 to the scan passageway 300 of the scanner.

Get the speed discrepancy between the rotating speed of the pickup roller assembly 10 after the one of the papers 200 is fed to the feeding roller assembly 30 and the rotating speed of the pickup roller assembly 10 which just picks up the one of the papers 200, when the speed discrepancy reaches the preset value set by the scanner, the scanner is triggered to start scanning.

The paper feeding method applied to the paper feeding device 100 which is mounted in the scanner, further includes a step of modulating the scaling of the scan according to the speeds of feeding forward the papers 200.

The paper feeding method applied to the paper feeding device 100 which is mounted in the scanner, further includes a step of detecting whether the paper jam problems are caused in the process of feeding the papers 200 by virtue of getting the pulse frequency variations of the velocity sensor 20.

The paper feeding method applied to the paper feeding device 100 which is mounted in the scanner, further includes a step of sending the instructions at the time of the paper jam problems being detected, and the motor 40 being stopped rotating.

As described above, the speeds of feeding forward the papers 200 are able to be detected in the real time by virtue of the velocity sensor 20 being fastened to the pickup shaft 11 of the pickup roller assembly 10 of the paper feeding device 100, and the scan scaling of the scanner is correspondingly modulated according to the speeds of feeding forward the papers 200, so that the scan images will be without being shortened or stretched in the scan process for improving the quality of the scan images. In addition, the speed discrepancy will be generated between the rotating speed of the pickup roller assembly 10 after the one of the papers 200 is fed to the feeding roller assembly 30 and the rotating speed of the pickup roller assembly 10 which just picks up the one of the papers 200, and the scanner is triggered to start scanning when the speed discrepancy reaches the preset value, so the papers 200 are able to be scanned in the real time in no need of the scan sensor. As a result, the scanner applying the paper feeding device 100 is capable of having a better scanning effect and a lower cost. 

1. A paper feeding device mounted in a scanner for feeding papers, the paper feeding device comprising: a motor; a pickup roller assembly connected with and driven by the motor for picking up the papers and transmitting the papers to the feeding roller assembly; a velocity sensor mounted to the pickup roller assembly for detecting rotating speeds of the pickup roller assembly so as to detect speeds of feeding forward the papers, the rotating speed of the pickup roller assembly being detected by virtue of counting pulses outputted by the velocity sensor; and a feeding roller assembly connected with and driven by the motor, and located in front of the pickup roller assembly for continuing feeding forward the papers; wherein a rotating speed of the feeding roller assembly is faster than the rotating speed of the pickup roller assembly, after one of the papers is fed to the feeding roller assembly, the feeding roller assembly drives the one of the papers to be fed acceleratedly, at the moment, the pickup roller assembly rotates acceleratedly on account of being dragged by the one of the papers, a speed discrepancy will be generated between the rotating speed of the pickup roller assembly after the one of the papers is fed to the feeding roller assembly and the rotating speed of the pickup roller assembly which just picks up the one of the papers, and when the speed discrepancy reaches a preset value set by the scanner, the scanner is triggered to start scanning.
 2. The paper feeding device as claimed in claim 1, wherein the pickup roller assembly includes a pickup shaft, a pickup roller pivotally mounted around one end of the pickup shaft, and the velocity sensor is mounted to the pickup shaft.
 3. The paper feeding device as claimed in claim 2, wherein the velocity sensor is an optical rotary encoder.
 4. The paper feeding device as claimed in claim 3, wherein the optical rotary encoder includes a light source, a coded disc and a light receiver, the coded disc is fastened to the pickup shaft, the coded disc is disposed between the light source and the light receiver, and when the motor drives the pickup roller assembly to rotate to pick up the papers, the pickup shaft and the coded disc rotate together at the same speed, but the light source and the light receiver do not rotate with the pickup shaft.
 5. The paper feeding device as claimed in claim 4, wherein the light source is turned on, the coded disc opens a plurality of equidistant openings arranged as a ring shape, and the light receiver receives light beams penetrating through the openings at the time of the pickup shaft and the coded disc rotating together.
 6. A paper feeding method applied to a paper feeding device which is mounted in a scanner for feeding papers, the paper feeding device including a motor, a pickup roller assembly connected with the motor, a velocity sensor mounted to the pickup roller assembly, and a feeding roller assembly connected with the motor, the paper feeding method comprising steps of: the motor driving the pickup roller assembly to rotate to pick up the papers and transmit the papers to the feeding roller assembly; the velocity sensor detecting rotating speeds of the pickup roller assembly by virtue of counting pulses outputted by the velocity sensor so as to detect speeds of feeding forward the papers; the motor driving the feeding roller assembly to rotate for continuing feeding forward the papers transmitted by the pickup roller assembly to a scan passageway of the scanner; and getting a speed discrepancy between the rotating speed of the pickup roller assembly after the one of the papers is fed to the feeding roller assembly and the rotating speed of the pickup roller assembly which just picks up the one of the papers; wherein the rotating speed of the feeding roller assembly is faster than the rotating speed of the pickup roller assembly, after one of the papers is fed to the feeding roller assembly, the feeding roller assembly drives the one of the papers to be fed acceleratedly, at the moment, the pickup roller assembly rotates acceleratedly on account of being dragged by the one of the papers, and when the speed discrepancy reaches a preset value set by the scanner, the scanner is triggered to start scanning.
 7. The paper feeding method as claimed in claim 6, further comprising a step of modulating a scan scaling of the scanner according to the speeds of feeding forward the papers.
 8. The paper feeding method as claimed in claim 6, further comprising a step of detecting whether paper jam problems are caused in the process of feeding the papers by virtue of getting pulse frequency variations of the velocity sensor.
 9. The paper feeding method as claimed in claim 8, further comprising a step of sending instructions at the time of the paper jam problems being detected, and the motor being stopped rotating.
 10. The paper feeding method as claimed in claim 6, wherein the pickup roller assembly includes a pickup shaft, a pickup roller pivotally mounted around one end of the pickup shaft, and the velocity sensor is mounted to the pickup shaft.
 11. The paper feeding method as claimed in claim 10, wherein the velocity sensor is an optical rotary encoder.
 12. The paper feeding method as claimed in claim 11, wherein the optical rotary encoder includes a light source, a coded disc and a light receiver, the coded disc is fastened to the pickup shaft, the coded disc is disposed between the light source and the light receiver, and when the motor drives the pickup roller assembly to rotate to pick up the papers, the pickup shaft and the coded disc rotate together at the same speed, but the light source and the light receiver do not rotate with the pickup shaft.
 13. The paper feeding method as claimed in claim 12, wherein the light source is turned on, the coded disc opens a plurality of equidistant openings arranged as a ring shape, and the light receiver receives light beams penetrating through the openings at the time of the pickup shaft and the coded disc rotating together. 